Reduced Energy Cartridge and Method of Making Same

ABSTRACT

A method of manufacturing a cartridge comprising providing a cartridge body with forward and rearward cavities interconnected by an aperture, providing a piston with a primer retaining cavity, inserting primer into the primer retaining cavity, securing the primer, placing a seal member around the piston, inserting the piston and seal member combination into the rearward cavity of the cartridge body, and crimping at least a portion of the cartridge body to the piston.

CROSS-REFERENCE TO RELATED APPLICATIONS

Not Applicable

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH

Not Applicable

FIELD OF THE INVENTION

The invention relates to cartridges for firearms that are designed for,or are temporarily or permanently modified to be used in, reality-basedtraining exercises. In particular, the invention relates to a two-piecereduced energy cartridge.

BACKGROUND OF THE INVENTION

Reduced energy cartridges for use in training or practice exercises arewell known. Regardless of what application it is used in, an importantcharacteristic of a firearm cartridge is its ability to cycle the slideon firearm. The forward momentum of a projectile creates recoil, orbackward momentum, in the firearm. If the recoil is sufficient, thefirearm is cycled. Projectiles of higher mass create more recoil thanprojectiles of lower mass, a result of the conservation of momentum.Training cartridges necessarily use low mass projectiles, and as aresult, cycling is a problem.

One design used to solve the cycling problem in training cartridges isthat of telescopically interfitted two-piece cartridges. After theexplosive material is ignited in such a two-piece cartridge, thelow-mass projectile, located in a first part of the cartridge, isexpelled from the firearm by a portion of the gas created upon ignition.The remaining gas created during ignition of the explosive material isused to drive a second part of the cartridge rearwardly to cycle thefirearm.

One objective in designing such a training cartridge is the minimizationof cost. Another objective is minimization of explosive material in thecartridge. The quantity of explosive material must be sufficient tocycle the firearm, but also low enough to prevent the projectile fromleaving the firearm at an unsafe velocity.

Information relevant to attempts to address these problems can be foundin the following U.S. patents and U.S. Patent Application Publications,the entire contents of each being incorporated herein by reference: U.S.Pat. Nos. 5,035,183; 5,359,937; 6,439,123; 6,575,098; and 2005/0183612.However, each one of these single-primer references suffers from one ormore of the following disadvantages: the use of excessively largequantities of explosive material that damages the bolt-face of thefirearm; complex component design; and/or complex component assembly.

The art referred to and/or described above is not intended to constitutean admission that any patent, publication or other information referredto herein is “prior art” with respect to this invention. In addition,this section should not be construed to mean that a search has been madeor that no other pertinent information as defined in 37 C.F.R. §1.56(a)exists.

All U.S. patents and applications and all other published documentsmentioned anywhere in this application are incorporated herein byreference in their entirety.

Without limiting the scope of the invention a brief summary of some ofthe claimed embodiments of the invention is set forth below. Additionaldetails of the summarized embodiments of the invention and/or additionalembodiments of the invention may be found in the Detailed Description ofthe Invention below.

A brief abstract of the technical disclosure in the specification isprovided to comply with 37 C.F.R. 1.72.

SUMMARY OF THE INVENTION

At least one embodiment of the present invention is directed toward amethod of manufacturing a cartridge for use in a firearm. The methodcomprises providing a cartridge body wherein a first portion of thecartridge body defines a forward cavity and a second portion of thecartridge body defines a rearward cavity. An aperture interconnects theforward and rearward cavities. The cartridge body is configured to bedisposed about at least a portion of a piston. The method furthercomprises providing a piston wherein the piston has a top end and abottom end. A portion of the bottom end defines a primer retainingcavity. A portion of the piston defines a gas passageway extending fromthe primer retaining cavity to the top end of the piston. The methodfurther comprises inserting a primer into the primer retaining cavity ofthe piston and securing the primer in the primer retaining cavity. Themethod further comprises placing a seal member around the piston,inserting the piston and seal member combination into the rearwardcavity of the cartridge body, and crimping at least a portion of thesecond portion of the cartridge body to the piston.

At least one embodiment of the present invention is directed towards acartridge for firearms. The cartridge includes a piston, a cartridgebody, a primer, and a seal member. The piston has a top end and a bottomend. A portion of the bottom end of the piston defines a primerretaining cavity. And, a portion of the piston defines a gas passagewaywhich extends from the primer retaining cavity to the top end of thepiston. A first portion of the cartridge body defines a forward cavityand a second portion of the cartridge body defines a rearward cavity. Anaperture interconnects the forward and rearward cavities. The cartridgebody is configured to be disposed about at least a portion of thepiston. At least a portion of the second portion of the cartridge bodyis crimped about the piston. A seal member is arranged around thepiston, forming a seal between the piston and an inner surface of therearward cavity of the cartridge body. The piston has two positions: anunfired position and a fired position. In the unfired position the topend of the piston is adjacent the aperture. In the fired position thepiston has sealingly slid rearward in the rearward cavity. A primer isarranged in the primer retaining cavity of the piston whereby uponfiring, the gas created by the primer flows through the gas passageway.A portion of the gas flows through the aperture, and a portion of thegas fills the rearward cavity between the seal and the aperture, whichcauses the piston to sealingly slide rearward.

These and other embodiments which characterize the invention are pointedout with particularity in the claims annexed hereto and forming a parthereof. However, for further understanding of the invention, itsadvantages and objectives obtained by its use, reference should be madeto the drawings which form a further part hereof and the accompanyingdescriptive matter, in which there is illustrated and describedembodiments of the invention.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S)

A detailed description of the invention is hereafter described withspecific reference being made to the drawings.

FIG. 1 is an exploded view of an embodiment of the present inventiondepicting the components of a cartridge.

FIG. 2 is cross-sectional view of an embodiment of the present inventiondepicting a cartridge in an unfired position.

FIG. 3 is a cross-sectional view of an embodiment of the presentinvention depicting a cartridge in a fired position.

FIG. 4 is a perspective cross-sectional view of an embodiment of thepresent invention depicting a cartridge body with a vent hole.

FIG. 5 is a perspective cross-sectional view of an embodiment of thepresent invention depicting a cartridge with a rupture disc.

FIG. 6 is a perspective cross-sectional view of an embodiment of thepresent invention depicting a cartridge with a rupture disc.

FIG. 7 is a perspective cross-sectional view of an embodiment of thepresent invention depicting a cartridge with a seal member integral tothe piston.

FIG. 8 is a flowchart of an embodiment of the present inventiondepicting a method of making a cartridge.

DETAILED DESCRIPTION OF THE INVENTION

While this invention may be embodied in many different forms, there aredescribed in detail herein specific preferred embodiments of theinvention. This description is an exemplification of the principles ofthe invention and is not intended to limit the invention to theparticular embodiments illustrated.

For the purposes of this disclosure, like reference numerals in thefigures shall refer to like features unless otherwise indicated.

Embodiments of the present invention make use of telescopicallyinterfitted two-part cartridges. The components are designed such thatthey can be easily produced and assembled at a lower cost than otherdesigns.

At least one embodiment of the present invention is directed toward afirearm cartridge. Examples of the components to be assembled into acartridge 10 are depicted in FIG. 1. The telescopically interfittedcartridge 10 of FIG. 1 is comprised of a cartridge body 20, a piston 25,a seal member 30, and a primer 35.

Referring to FIGS. 2 and 3, the cartridge body 20 has five primarydesign features: a forward cavity 40 that retains a projectile; arearward cavity 45 (as best seen in FIG. 3) into which the piston 25 isinserted; a divider 50 which separates the forward and rearwardcavities; an aperture 55 within the divider 50 interconnecting theforward and rearward cavities, the aperture 55 acting to limit the gasflow to a projectile thereby limiting the projectile's velocity; and atop chamfer 60 which aids in feeding cartridges into the magazine andthe firearm. It should be noted that the top chamfer 60 is not requiredin all embodiments of the invention.

As mentioned above, the cartridge 10 also comprises a piston 25 whereinthe piston has a top end 65 and a bottom end 70. A portion of the bottomend 70 defines a primer retaining cavity 75 for retaining the primer, asbest seen in FIGS. 2 and 3. A portion of the piston defines a gaspassageway 80 extending from the primer retaining cavity 75 to the topend 65 of the piston.

Still referring to FIGS. 2 and 3, the cartridge body 20 is configured tobe disposed about at least a portion of the piston 25, thus forming atelescopically interfitted two-part cartridge 10. The inner diameter 85of the cartridge body 20 and the outer diameter 90 of the piston 25 areconfigured to allow the piston body 25 to be inserted into the cartridgebody 20.

The function of the piston before firing is to hold the seal member 30and primer 35 in place. Referring now to FIG. 2, which depicts thecartridge 10 in an unfired state, the top end 65 of the piston isadjacent the divider 50. The piston 25 is almost completely containedwithin the rearward cavity 45 of the cartridge body 20. Furthermore, aportion 92 of the cartridge body is crimped to the piston 25. As bestseen in FIG. 3, which depicts the cartridge 10 in a fired state, crimpedportion 92 impacts protrusion 93 after firing. Because the innerdiameter of the crimped portion 92 is less than the outer diameter ofthe protrusion 94, the piston and cartridge body do not physicallyseparate after firing. Instead, after firing the piston slidesrearwardly, remaining slidingly engaged to the cartridge body in atelescopic manner.

The seal member 30 provides a seal between the piston 25 and cartridgebody 20 so that the entire travel of the piston, from an unfiredposition to a fired position, is sealed. Gases created upon firingescape only through the aperture 55. More specifically, upon initiationof the primer, gas travels through the gas passageway 80 and reaches thedivider 50. The gas fills the portion of the rearward cavity between thecartridge body 20, the piston 25, and the seal member 30. The sealmember 30 prevents the gas from escaping rearwardly.

In a primer-only embodiment, the term “primer” as used herein includesany detonating gas generator. In some embodiments, the present inventionutilizes a gas generating primer that relies on heat to increaseinternal pressure: Gas is generated then heated. This creates anexpansion of less gas to more volume than cooler systems. Informationrelated to such a gas generating primer can be found in the pending U.S.patent application entitled “NON-TOXIC PERCUSSION PRIMERS AND METHODS OFPREPARING THE SAME”, Attorney Docket No. A39.2B-13252-US01, the entirecontents of which are incorporated herein by reference.

In some embodiments, the cartridge body 20 further includes a vent hole96, as depicted in FIG. 4, in order to allow gases to escape and furtherreduce the energy available to the projectile. The vent hole 96 isdesirably placed forward the top end 65 of the piston when the piston isin the fired position. A person of skill in the art will recognize thatthe size of the vent hole will vary, depending on the primer/propellantsystem used. However, in some embodiments the size of the vent hole isapproximately 0.050 inches.

At least one embodiment of the present invention employs the use of arupture disc 98 to regulate internal pressures, as shown in FIGS. 5 and6. In FIG. 5 the rupture disc 98 is placed within the rearward cavity 45and adjacent the aperture 55. FIG. 6 depicts another embodiment of arupture disc 98, with the disc 98 placed within the gas passageway 80.In some embodiments, the rupture disc 98 has a thickness ofapproximately 0.010 inches.

In at least one embodiment, the seal member 30 is an O-ring, as depictedin FIGS. 1-3. However, one skilled in the art will recognize that anumber of other seal members may be used to accomplish the sealingeffect created by the O-ring.

In another embodiment, the seal member is integral to the piston 25, asshown in FIG. 7. As seen in FIG. 7, the design of the piston 25 haseliminated the need for a separate seal member.

In some embodiments of the present invention, a propellant 94 is furtherincluded in the piston 25, as shown in FIG. 2. One of skill in the artwill recognize that there are a variety of materials that can be used asa propellant, such as single or double based propellants. In at leastone embodiment, the propellant 94 is placed within the gas passageway 80of the piston.

As mentioned above, in some embodiments, the cartridge 10 is alsomanufactured with a projectile 95. In at least one embodiment, theprojectile 95 is comprised of a cup 100, a marking material 105, and acap 110, as depicted in FIG. 1. In one embodiment, the projectile 95 isinserted into the forward cavity 40 of the cartridge body 20. Afterfiring, as gas escapes from the rearward cavity 45 to the forward cavity40 through the aperture 55, the projectile 95 is forced from the forwardcavity and out the barrel of the firearm.

It should be noted that in other embodiments, the projectile 95 iscomprised of a rubber bullet, a blank, or oleoresin capsicum spray. Oneof ordinary skill should recognize that there are a number of otherprojectiles that can be substituted for any of the above examples.

At least one embodiment of the present invention is directed toward amethod of manufacturing the cartridge described above, as depicted inthe flowchart in FIG. 8. The method comprises the step 200 of providinga cartridge body 20 and a piston 25, as described above.

The method further comprises the step 210 of priming the piston 25. Thisstep involves inserting a primer 35 into the primer retaining cavity 75of the piston.

After the primer 35 has been inserted into the piston 25, the methodfurther comprises the step 215 of securing the primer in the primerretaining cavity 75. One of skill in the art will recognize that thereare a number of ways the primer may be secured within the primerretaining cavity. In one embodiment, securing the primer to the pistoninvolves staking the piston. One method of staking the piston may entailusing a machine to push inwardly portions of the piston materialsurrounding the primer. Once sufficient material has been pushedinwardly, the primer will be securingly retained within the primerretaining cavity.

After the primer is staked, the method further comprises the step 225 ofplacing a seal member 30 around the piston.

Next, the method further comprises the step 230 of inserting the pistonand seal member combination into the rearward cavity 45 of the cartridgebody 20. As stated above, the inner diameter 85 of the cartridge body 20and the outer diameter 90 of the piston 25 are configured to allow thepiston 25 to be inserted into the cartridge body 20.

Still referring to FIG. 8, the method further comprises the step 235 ofcrimping at least a portion 92 of the cartridge body 20 to the piston25. In one embodiment, the crimped portion 92 is located as close to thebottom end 70 of the piston as possible, thus allowing the greatestamount of travel.

In some embodiments, the step 235 of crimping is performed by twopartially annular jaws. The cartridge is placed within jaws and as theyare brought together by a predetermined force, through a predetermineddistance, or some other measurement used by those skilled in the art, aportion of the cartridge body is compressed onto the piston.

In at least one embodiment, the step 235 of crimping comprises crimpingthe bottom portion of the cartridge body so that the inner diameter 85of the rearward cavity in the crimped portion is less than the innerdiameter 85 of the rest of the rearward cavity 45, as seen in FIG. 2.

As a non-limiting example, some embodiments of cartridge bodies beforecrimping have an outer diameter of approximately 0.359 inches and aftercrimping have an outer diameter of approximately 0.350 inches. Thesedimensions will vary with other embodiments because the size of thefirearm may dictate larger or small cartridges, however this ratio asproved to be sufficient to secure the cartridge body and the piston.

In at least one embodiment, the method further includes the step 240 ofinserting a projectile 95. The step of inserting a projectile maycomprise inserting a cup 100 into the forward cavity 40 of the cartridgebody. Then, a marking material 105, such as ink or some other agent formarking known by those skilled in the art, is distributed into the cup100. Although amounts may vary depending on the size of the cartridgeand the amount of marking material desired, an amount of material insome embodiments is 1.5 grains. A cap 110 is then inserted into the cup100 and marking material combination.

The step 240 of inserting the projectile 95 can be performed at variousstages of manufacture. In some embodiments, the step of inserting theprojectile is performed prior to the step 230 of inserting the pistonand seal member combination into the cartridge body. In such anembodiment, it may be desirable to further include a step 245 ofinverting the cartridge body and projectile combination prior to thestep 230 of insertion of the piston and seal member combination. Also,it may be desirable in such an embodiment to further include a vent 125in cup 100, as depicted in FIG. 1. The vent 125 may prevent theprojectile from becoming dislodged from the forward cavity 40 during thestep of piston insertion into the cartridge body.

In at least one embodiment, the method also comprises the step 250 ofinspecting the piston for damage. In one embodiment, the inspection step250 is performed immediately after the step 215 of securing the primerin the primer retaining cavity. The inspection step 250 ensures that theprimer has not been damaged during securement. Additionally, theinspection step 250 ensures that the primer has been fully secured tothe piston.

In some embodiments, a first machine performs the steps of primerinsertion, primer securement, and piston inspection. A second machineperforms the steps of placing the seal member, inserting the piston andseal member combination into the cartridge body, and crimping thecartridge body.

In some embodiments, after the primer and piston combination leaves thefirst machine, it may be placed into a feeder bowl of the secondmachine. The second machine may stretch a seal member, drawn fromanother feeder bowl, and place it over a piston. Also, the secondmachine may draw a cartridge body from a feeder bowl, draw a cup fromanother feeder bowl, and insert the cup into the forward cavity of thepreviously drawn cartridge body. A marking material is then distributedinto the cup by the second machine, and a cap is drawn from a feederbowl and inserted into the cup and marking material combination.

In at least one embodiment, the second machine then inverts thecartridge and projectile combination. At this point, the second machinemay then insert the piston into the cartridge body and the secondmachine crimps the cartridge body to the piston, after which thecartridge is placed in a tray as a finished unit.

The above description should make clear the advantages of the presentinventive methods of manufacturing a cartridge. The components, inparticular the cartridge body and the piston, are designed such thatthey can be easily produced and assembled. At least one embodiment ofthe present invention eliminates complicated piston and cartridge bodyalignment requirements. Furthermore, at least one embodiment of thepresent invention uses less primer than that required by other designs,thereby reducing or eliminating damage to the gun's bolt face whilestill having enough energy to cycle the firearm.

The above disclosure is intended to be illustrative and not exhaustive.This description will suggest many variations and alternatives to one ofordinary skill in this art. The various elements shown in the individualfigures and described above may be combined or modified for combinationas desired. All these alternatives and variations are intended to beincluded within the scope of the claims where the term “comprising”means “including, but not limited to”.

Further, the particular features presented in the dependent claims canbe combined with each other in other manners within the scope of theinvention such that the invention should be recognized as alsospecifically directed to other embodiments having any other possiblecombination of the features of the dependent claims. For instance, forpurposes of claim publication, any dependent claim which follows shouldbe taken as alternatively written in a multiple dependent form from allprior claims which possess all antecedents referenced in such dependentclaim if such multiple dependent format is an accepted format within thejurisdiction (e.g. each claim depending directly from claim 1 should bealternatively taken as depending from all previous claims). Injurisdictions where multiple dependent claim formats are restricted, thefollowing dependent claims should each be also taken as alternativelywritten in each singly dependent claim format which creates a dependencyfrom a prior antecedent-possessing claim other than the specific claimlisted in such dependent claim below.

This completes the description of the embodiments of the invention.Those skilled in the art may recognize other equivalents to the specificembodiment described herein which equivalents are intended to beencompassed by the claims attached hereto.

1. A cartridge comprising: a piston, the piston having a top end and abottom end, a portion of the bottom end defining a primer retainingcavity, and a portion of the piston defining a gas passageway extendingfrom the primer retaining cavity to the top end of the piston; acartridge body, a first portion of the cartridge body defining a forwardcavity and a second portion of the cartridge body defining a rearwardcavity, the forward and rearward cavities being interconnected by anaperture, the cartridge body configured to be disposed about at least aportion of the piston; a primer arranged in the primer retaining cavity;a seal member arranged around the piston and forming a seal between thepiston and an inner surface of the rearward cavity of the cartridgebody; the piston having two positions, an unfired position wherein thetop end of the piston is adjacent the aperture, and a fired positionwherein the piston has sealingly slid rearward in the rearward cavity;wherein at least a portion of the second portion of the cartridge bodyis crimped about the piston, and whereby upon firing, the gas created bythe primer flows through the gas passageway, a portion of the gas flowsthrough the aperture, and a portion of the gas fills the rearward cavitybetween the seal and the aperture, which causes the piston to sealinglyslide rearward.
 2. The cartridge of claim 1, further comprises apropellant.
 3. The cartridge of claim 2, wherein the propellant isdistributed within the gas passageway.
 4. The cartridge of claim 1,further comprising a projectile.
 5. The cartridge of claim 4, whereinthe projectile comprises a marking material.
 6. The cartridge of claim4, wherein the projectile is selected from the group consisting of arubber bullet, a blank, and oleoresin capsicum spray.
 7. The cartridgeof claim 1, wherein the crimped portion of the cartridge body is crimpedso that the inner diameter of the rearward cavity in the crimped portionis less than the inner diameter of the rest of the rearward cavity. 8.The cartridge of claim 1, wherein the cartridge body further comprises achamfer.
 9. The cartridge of claim 1, wherein the cartridge body furthercomprises at least one vent hole.
 10. The cartridge of claim 1, whereinthe cartridge body further comprises at least one rupture disc.
 11. Amethod of manufacturing a cartridge for use in a firearm, the methodcomprising: (a) providing a cartridge body, a first portion of thecartridge body defining a forward cavity and a second portion of thecartridge body defining a rearward cavity, the forward and rearwardcavities being interconnected by an aperture, the cartridge bodyconfigured to be disposed about at least a portion of a piston; (b)providing the piston, the piston having a top end and a bottom end, aportion of the bottom end defining a primer retaining cavity, and aportion of the piston defining a gas passageway extending from theprimer retaining cavity to the top end of the piston; (c) insertingprimer into the primer retaining cavity of the piston; (d) securing theprimer in the primer retaining cavity; (e) placing a seal member aroundthe piston; (f) inserting the piston and seal member combination intothe rearward cavity of the cartridge body; and (g) crimping at least aportion of the second portion of the cartridge body to the piston. 12.The method of claim 11, further comprising inserting a projectile intothe forward cavity of the cartridge body.
 13. The method of claim 12,wherein inserting the projectile comprises: (a) inserting a cup into theforward cavity; (b) distributing a marking material into the cup; and(b) inserting a cap into the cup and marking material combination. 14.The method of claim 13, wherein inserting the projectile is performedprior to the inserting the piston and seal member combination into thecartridge body.
 15. The method of claim 14, further comprising invertingthe cartridge body prior to inserting the piston and seal membercombination into the cartridge body.
 16. The method of claim 11, whereinsecuring the primer in the primer retaining cavity comprises staking thepiston.
 17. The method of claim 11, wherein crimping is performed by twopartially annular jaws.
 18. The method of claim 11, wherein crimpingcomprises crimping the bottom portion of the cartridge body so that theinner diameter of the rearward cavity in the crimped portion is lessthan the inner diameter of the rest of the rearward cavity.
 19. Themethod of claim 11, wherein (c) and (d) are performed by a first machineand (e) thru (g) are performed by a second machine.
 20. The method ofclaim 11, further comprising inspecting the piston for damage.
 21. Themethod of claim 20, wherein inspecting the piston is performedimmediately after securing the primer in the primer retaining cavity.22. The method of claim 21, wherein (c) and (d), and inspecting thepiston are performed by a first machine and (e) thru (g) are performedby a second machine.
 23. A method of manufacturing a cartridge for usein a firearm, the method comprising: (a) providing a cartridge body, afirst portion of the cartridge body defining a forward cavity and asecond portion of the cartridge body defining a rearward cavity, theforward and rearward cavities being interconnected by an aperture, thecartridge body configured to be disposed about at least a portion of apiston; (b) providing the piston, the piston having a top end and abottom end, a portion of the bottom end defining a primer retainingcavity, and a portion of the piston defining a gas passageway extendingfrom the primer retaining cavity to the top end of the piston; (c)inserting primer into the primer retaining cavity of the piston; (d)securing the primer in the primer retaining cavity; (e) inspecting thepiston for damage; (f) placing a seal member around the piston; (g)inserting a projectile into the forward cavity of the cartridge body;(h) inserting the piston and seal member combination into the rearwardcavity of the cartridge body; and (i) crimping at least a portion of thesecond portion of the cartridge body to the piston.